(p. 1462) Host–pathogen interactions in the critically ill 

Infection by a pathogenic micro-organism triggers a coordinated activation of both innate and adaptive immune responses. The innate immune response quickly triggers an antimicrobial response that will initiate development of a pathogen-specific, long-lasting adaptive immune response. Accurate recognition of microbial-associated molecular patterns by pattern-recognition receptors (PRRs) is the cornerstone of this immediate response. Most studied PRRs are Toll-like receptors (TLRs) and their kinase signalling cascades that activate nuclear transcription factors, and induce gene expression and cytokine production. Deficiencies or genetic variability in these different signalling pathways may lead to recurrent pyogenic infections and severe invasive diseases. After initial contact between the host and pathogen, numerous factors mediate the inflammatory response, as pro-inflammatory cytokines and chemokines. Apart from host genetic variability, pathogen diversity also influences the phenotypic features of various infectious diseases. Genomic analysis may assist in the development of targeted therapies or new therapeutic strategies based on both patient and microorganism genotype.